WHO suspends hydroxychloroquine arm in global COVID-19 trial amid safety review

The World Health Organization (WHO) has implemented a temporary pause of the hydroxychloroquine arm within the agency’s Solidarity Trial in COVID-19 patients pending a review of safety data by the study’s Data Safety Monitoring Board, said WHO Director General Tedros Adhanom Ghebreyesus on May 25. He stated that “this concern relates to the use of hydroxychloroquine and chloroquine in COVID-19,” but noted that the other arms of the trial are continuing.

The study is comparing four treatment options against standard of care, to assess their relative effectiveness against COVID-19. Specifically, the trial is assessing the experimental antiviral remdesivir, HIV drug combination lopinavir/ritonavir, interferon beta-1a, which is used to treat multiple sclerosis, and the antimalarial drugs chloroquine and hydroxychloroquine. So far, over 400 hospitals in 35 countries are actively recruiting participants and nearly 3500 patients have been enrolled from 17 countries, according to Tedros.

He said the safety review will consider data collected so far in the Solidarity Trial, particularly “robust randomised available data, to adequately evaluate the potential benefits and harms from this drug.”

The WHO chief cited findings from a registry analysis published on May 22 in The Lancet that included nearly 15,000 people treated with hydroxychloroquine or chloroquine, either alone or with a macrolide. The authors said “we were unable to confirm a benefit of hydroxychloroquine or chloroquine, when used alone or with a macrolide, on in-hospital outcomes for COVID-19,” adding that “each of these drug regimens was associated with decreased in-hospital survival and an increased frequency of ventricular arrhythmias when used for treatment of COVID-19.”

Mike Ryan, head of the WHO emergencies programme, said no signals have emerged in the Solidarity Trial that would suggest any problem, and that the decision to temporarily suspend the hydroxychloroquine arm had been taken out of “an abundance of caution.” Meanwhile, WHO chief scientist Soumya Swaminathan stated that it’s important to continue to gather evidence on the efficacy and safety of hydroxychloroquine, adding the decision to pause testing in the hydroxychloroquine arm will be reviewed in the next week or two.